(1) Field of the Invention
This invention relates to agriculture and more particularly to row followers forming a portion of an agricultural vehicle guidance system. As used herein, "agricultural vehicle" or "vehicle" means a wheeled vehicle normally used on a farm such as used for harvesting, planting, or tilling. These vehicles are sometimes called strippers, pickers, combines, or tractors.
Farmers are the ones having ordinary skill in this art.
(2) Description of the Related Art
As set out in the BARNES et al U.S. Pat. No. 5,121,799, it is desirable to have a vehicle which can be guided along a designated path. Normally the designated path by which the vehicle will be guided will be a row which might be either a series of stalks, as described in the BARNES et al U.S. Pat. No. 5,148,873, or it might be a furrow as shown in U.S. Pat. No. 5,121,799, as well as U.S. Pat. No. 5,148,873. Also, U.S. Pat. No. 5,185,990 identified above illustrates a row follower to follow the stalks.
An encoder as shown in U.S. Pat. No. 5,148,873 is used to measure the deviation of the row follower from the vehicle to indicate corrections to be applied to the steering mechanisms of the vehicle as more fully set out in U.S. Pat. No. 5,121,799.
Problems have been encountered with the encoders which are believed to include rough handling, or shock to the encoders, particularly to the rotating shaft of the encoder within the body of the encoder.
Another source of problem with the encoders is believed to be environmental inasmuch as in the agriculture processes there is usually dust and sand which are stirred up and which tend to infiltrate the housing of the encoder. Also normally, agricultural vehicles are not housed within a closed building and are often left exposed to rain, snow, and dew, as well as the dust and sand.